The White House is hinting that President Barack Obama will soon announce new steps significantly relaxing relations with Cuba in what would be the biggest thaw in US relations with the island in decades.

The proposed changes, signalled ahead of the Summit of the Americas in Trinidad and Tobago later this month, would soften regulations limiting travel by US citizens to Cuba and the remittances of money by Cuban-Americans to the island.

The move comes as members of the US Congressional Black Caucus held meetings this week with both President Raul Castro and his brother, the former president Fidel Castro. On their return to Washington they suggested that both men had displayed unexpected warmth and curiosity about President Obama and his intentions.

"He really wants President Obama to succeed," Congresswoman Laura Richardson, a Democrat from California, said of Fidel Castro. "He sincerely wants an opportunity, I think, in his lifetime to see a change in America." She added that he had "looked directly into our eyes" and asked, "How can we help President Obama?"

While the ice that encases relations between Cuba and the US may finally be showing signs of breaking up, no one is betting that Mr Obama will go so far as to order any change to the trade embargo that the US has imposed on Cuba for nearly 50 years. There remain powerful forces on Capitol Hill and in the Cuban-American community who remain firmly opposed to it.

Changes in the rules on travel and money remittances alone would nevertheless be seen as a vital first step in a longer strategy to relieve the isolation of the Cuban people from the United States. A bi-partisan bill calling for precisely such a relaxation, which would allow virtually any American to visit the island, was introduced to both the Senate and the House of Representatives last month.

Noting the visit to the island by the Black Caucus members, Jeffrey Davidow, White House adviser to the President on the Summit of the Americas, said he "would not be surprised" if Mr Obama announces changes in US policy before the meeting. Six members of Congress, all Democrats, met President Castro on Monday, the first meeting he has held with American politicians since taking over from his brother who was struck by illness 14 months ago. Three of the group then met Fidel Castro on Tuesday. Likewise, it was his first such meeting since his illness struck.

The US representatives reported that the elder Castro was "very healthy, very energetic, very clear thinking" – remarks that should lay to rest, at least for a while, the rumours that the former president is on the brink of death.

Though his brother now runs the country and this year seems to have taken a more independent stance, replacing several senior members of the government, Fidel still wields influence.

Fidel Castro hailed this week's meeting with the members of Congress. "Cuba did not have any alternative but to take the initiative," to arrange the meetings, he wrote in a column, saying Cuban leaders "weren't aggressors, nor did we threaten the United States". He also praised members of the US delegation for the "the quality of their simple and profound words".

Raul Castro had made it clear that "everything was on the table" regarding the future of US-Cuba relations, said Barbara Lee, one of the three members of the group who also saw Fidel.

Representative Bobby Rush remarked that Raul Castro is "just the opposite" of how he is portrayed in the media. "I think what really surprised me but also endeared me to him was his keen sense of humour, his sense of history and his basic human qualities."

Pressure for change in America's ties with Cuba continues to simmer on Capitol Hill, particularly from President Obama's party.

Additionally, the powerful agricultural lobby in the US, with Democratic and Republican supporters, is asking for an end to restrictions that have hampered exports of farm products to Cuba such as beef and cereals.

"For the past 50 years, the United States has been swimming in the Caribbean sea of delusion" with its belief that by isolating Cuba it would somehow bring down the Castro regime, argued Congressman Emmanuel Cleaver, who was also on the visit. Yet, 50 years after the socialist revolution that put Fidel Castro in power, "we are the only nation that is isolated," he said.

Talk of reversing years of US policy towards the Communist regime in Cuba will not wash with many Republicans or those of either party with large Cuban-American constituencies. Among those is the Democrat New Jersey Senator Robert Menendez, who has vowed to fight any changes to the rules.

"Our great nation should stand for human freedom and democracy and against underwriting regimes that oppress, suppress and murder," he said after fellow senators introduced legislation to end the travel ban.

From deep-freeze to thaw: A brief history of US-Cuban relations

1960 After US businesses in Havana are nationalised, US imposes partial trade embargo.

1961 Congress formalises the embargo with the Foreign Assistance Act.

1963 Kennedy seeks to end trade embargo but is killed a month later.

1975 US ends sanctions against foreign countries that trade with Cuba.

1979 Cuban Americans allowed to visit home; 100,000 make the trip in 1980.

1981 President Reagan elected and immediately tightens the embargo.

1992 Cuban Democracy Act stops Cubans in US sending money home.

1996 After Cuba shoots down two US aircraft, embargo is strengthened.

2000 Congressional vote allows food and medicine to be sold to Cuba.

2002 Jimmy Carter makes first visit by former or current president since 1959.

2003 President Bush acts to tighten travel restrictions.

2006 10 US legislators visit Cuba but do not meet Raul or Fidel Castro.

April 2009

The Obama administration announces remittance and travel restrictions on Cuban Americans will be lifted.